metamorphic

Likely amphibolite

Amphibolite, composed mainly of hornblende and plagioclase feldspar

AI-generated identification · may be incorrect

Dark gray to black, coarse crystalline and weakly foliated, with pale mineral bands or patches. Typical minerals have Mohs hardness around 5–6; the rock has no single crystal structure or cleavage.

Identified September 26, 2026More metamorphic →

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Physical properties

Dark gray to black, coarse crystalline and weakly foliated, with pale mineral bands or patches. Typical minerals have Mohs hardness around 5–6; the rock has no single crystal structure or cleavage.

Formation & geological history

Forms when basalt or gabbro is metamorphosed under medium- to high-grade heat and pressure, commonly during mountain building. Its age cannot be determined from the image.

Uses & applications

Used as crushed stone and, when attractive and durable, as dimension stone or landscaping material.

Geological facts

The pale streaks may be quartz or feldspar veins, but their identity cannot be confirmed visually.

Field identification & locations

Amphibolite is identified by its dark, hornblende-rich appearance and interlocking crystals; it occurs in metamorphic belts worldwide. A close-up or simple mineral tests would be needed to confirm the identification.